1. Field of Invention
The invention relates to an infusion pump for the delivery of a quantity of medicament to the body of a patient determinable by means of an electronic control device, the pump being provided with a computer for calculating the maximum permitted delivery quantity as a function of the previously delivered quantity and a blocking device for preventing further medicament delivery on exceeding a predetermined, permitted maximum value.
2. Description of the Prior Art
Such infusion pumps are used for supplying a patient with a medicament over a long time period and the medicament quantity continuously delivered by the infusion pump corresponding to the needs of the patient can be adjusted.
DE 33 90 462 C2 discloses an implantable infusion pump equipped with a computer, which determines the medicament quantity delivered over a “sliding time window/slot,” e.g. over three hours and blocks further delivery if the quantity delivered over this time period exceeds a maximum value.
However, this procedure is inadequate and the sliding time window length random. In many cases, such as e.g. with an attack of pain, it is necessary to briefly considerably raise the quantity of active substance to be delivered by the pump in order to rapidly raise the active substance level. However, whereas a quantity distributed over three hours can be tolerated, this can prove toxic when administered over three minutes. However, an infusion rate allowed when distributed over three hours, can prove toxic or even lethal when the administration extends beyond three hours. This problem cannot be solved with the “sliding time window.”
The problem of the invention is to provide an implantable infusion pump making it possible to reliably determine in each case the allowed delivery quantity.